Palestinian chief negotiator Saeb Erekat said on Monday that Israel's decision to construct nearly 500 new housing units in the West Bank prior to declaration of a settlement freeze further undermined any belief that it is a credible partner for peace.

"Israel's decision to approve the construction of over 450 new settlement units nullifies any effect that a settlement freeze,when and if announced, will have," Erekat said in a statement.

Defense Minister Ehud Barak signed some of the permits needed to construct the 455 new houses in West Bank settlements on Sunday night and was set to approve the remainder on Monday.

The new housing, which was decided on by Prime Minister Benjamin Netanyahu, will be built in six settlements, all of which are included in the settlement blocs that Israel wants to keep under any peace agreement. The settlements in question include the blocs of Har Gilo, Modi'in Ilit and Ariel.

It was not immediately clear when ground would be broken for the new homes. Yariv Oppenheimer of the Israeli anti-settlement movement Peace Now said that in the past it usually took up to a year before building began after permits were issued.

The Defense Ministry outlined the following construction plans: 149 homes in the settlement of Har Gilo, 12 in Alon Shvut, 84 in Modiin Ilit, 76 in Pisgat Zeev, 25 in Kedar, 20 in Maskiot and 89 in Ma'aleh Adumim.

Most of those settlements are near Jerusalem. The others are in the Jordan Valley to the east or close to central Israel.

An Israeli government source told Haaretz on Monday that U.S. Mideast Envoy George Mitchell and the Obama administration have been updated on the new housing permits.

The same source also said that the new permits were approved with the understanding that in return, Israel would enact a freeze on other settlement projects.

White House spokesman Robert Gibbs reiterated Washington's opposition to the move after Monday's announcement. When asked if he had hoped the U.S. condemnation issued last Fridaty would head off such approval, he told reporters: "I think the decision had been made before that."

The construction permits will take effect before the building freeze that Israel is now negotiating with the United States goes into force. But even during this freeze, work will continue on some 2,500 apartments that are currently under construction.

Netanyahu told the ministers of his Likud party on Sunday that an agreement on the partial settlement freeze will be finalized during special Mitchell's upcoming visit to Israel.

Though several ministers commented on the planned freeze before Sunday's cabinet meeting, the only one who assailed it was National Infrastructure Minister Uzi Landau (Yisrael Beiteinu). "There is no sense in freezing construction in the settlements."

"That will only increase the diplomatic pressure, just as happened after [Netanyahu's] speech at Bar-Ilan [University]," he said, referring to Netanyahu's first major policy speech delivered in June.

In contrast, Tourism Minister Stas Misezhnikov, also of Yisrael Beiteinu, praised Netanyahu for refusing to impose a total freeze on either East Jerusalem or the settlement blocs. However, he added, "we need to see what the other side will pay in exchange for these steps."